1. Field of the Invention
The present invention relates generally to wiper systems and, more particularly, to wiper systems used on motor vehicles for cleaning the windshields, rear windows and headlights.
2. Description of the Prior Art
Wiper systems basically comprise a wiper arm to which is attached a wiper blade including a superstructure or holder linked, by means of several claws, to a resilient wiping element or squeegee through intermediate backing strips located in lateral recesses provided in the wiping element.
Any wiper blade manufacturer has to solve a certain number of technical problems which first depend on the general form and on the dimensions of the surfaces to be cleaned and, second, depend on the specific qualities that the manufacturer wishes to give to his wiper blades.
Among the qualities a wiper blade should have, the following may be cited:
substantially uniform pressure distribution all along the wiping element on flat surfaces as well as on curved surfaces;
good anti-wind properties, i.e. the wiper blades should resist the action of the wind which tends to lift the wiper blade from the surface to be cleaned;
low production costs, for example in developing a wiper blade comprising the least possible parts.
Up to now most backing strips were flat, straight blades to which, before assembly, a certain curvature was superimposed. Other known backing strips have a flexibility diminishing continuously or discontinuously from their two extremities towards the center of the strips. This diminishing flexibility is generally obtained in increasing the transverse cross section of the backing strips.